Joseph Pisegna, MD

Professor, Department of Medicine, Chief, Division of Gastroenterology, Hepatology and Parenteral Nutrition, Veterans Administration Greater Los Angeles Healthcare System/ Wadsworth VA

Dr. Pisegna’s main research interest is the molecular pharmacology of hormones and receptors in the gastrointestinal tract. These research and clinical interests derive from research in the biochemistry and physiology of neuroendocrine tumors as well as an understanding of the molecular interaction of peptide hormones and their receptors. His clinical efforts are currently focused on the management of gastric hypersecretory conditions, neuroendocrine tumors of the GI tract, and Zollinger Ellison Syndrome (ZES), medical conditions that derive from alterations in the expression of gastrointestinal hormones. Dr Pisegna cloned the receptor for pituitary adenylate cyclase activating polypeptide (PACAP), which is in the vasoactive intestinal polypeptide family of peptides and the calcitonin gene related peptide (CGRP). He has demonstrated that PACAP is a potent stimulant of gastric acid secretion and is expressed on neurons innervating the stomach, with enterochromaffin-like cells (ECL) of the stomach expressing receptors for PACAP. Using mice lacking the PAC1 receptor, he has demonstrated that the mice develop a gastric acid hypersecretory condition resulting from hypergastrinemia. Recently developed VIP knockout mice have been demonstrated to have abnormal gastrointestinal motility. More recently Dr. Pisegna's research interests extend to understanding the mechanisms involved in satiety with a research focus in treating obesity disorders.